Hybridisation of Road Transport

Microsoft Word - roadmap_hybridisation_of_road_transport_01-06-2011.docHybridisation of Road Transport page 2 of 45
Table of Contents:
4. Hybrid solutions in Road Transport 13
4.1 The various Hybrid configurations for Passenger Cars 13
4.2 The Hybrid options for Commercial Vehicles 23
4.3 Non electrical Hybrid systems 25
4.4 Requirements for energy storage systems 27
5. Milestones 29
6. Roadmaps 35
7. Recommendations 40
9. References 44
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1. Executive Summary
The Green House Gas emission, especially the CO2 emission and the air quality in cities and
conurbation are major societal challenges not only for road transport. ERTRAC has addressed these
challenges in its new Strategic Research Agenda. But, road transport has to contribute its part
because only to overcome these challenges will secure sustainable person mobility (individual
mobility with the choice of your own means of transportation as well as to use all the possibilities of
public transport) and goods transport for the future, a basic requirement that humans will
presuppose as self-evident also in the future.
In the context of sustainable mobility the propulsion technology carry the main load to overcome the
problems of environmental impact and air quality.
The electrification of vehicle drive trains is an important step to increase energy security,
improvement of air quality and CO2 reduction. The European Commission launched a set of initiatives
to become leadership in the electrification technology, the Fuel Cell and Hydrogen Initiative, the
Electrification of Road Transport Strategy paper developed within the framework of the Green Car
Initiative, are just some to mention.
The following document ‘Hybridisation of Road Transport’ is based on the consensus of experts of
major companies and organisations from the European Road Transport Research Advisory Council
(ERTRAC) and its Expert Group Enabling Technology.
Hybrid Vehicles will play a major role for long time, well beyond 2030, they are a major enabler to
reach the CO2 targets, to reduce the Green House Gas emission in general, to enable good air quality
in urban areas and to spare the energy consumption. Since Hybrid Vehicles do not have the range
limitations of Full Electric Vehicles and also not the drawback of emissions like the pure internal
combustion engine vehicles, they will be more in line with the consumer’s needs in the future and
the driving pattern of today and those for the future. Hybrid Electric Vehicles combine the
advantage of two different propulsion systems, the possibility to drive with zero emission and to
drive on long distances.
The benefits of Hybrid Electric Vehicles, no other propulsion can deliver in mid term perspective,
shows very clear that they will be an important part to secure sustainable mobility:
- The decarbonisation advantage, 10%-95% CO2 reduction potential
- The ‘green car’ advantage, zero emission driving in electric mode in cities and
conurbation, driving without making air quality worse
- The consumer advantage, driving without limited range from city to city as well as all
over the landscape, with ultra low emissions with the optimised ICE and transmission
mode in the future, the use of alternative-/bio-fuels and thus reduced fuel consumption
and costs in real life operation and lower emission.
- The economical advantage. With all these benefits, the use of hybrid vehicles will gain
benefits on economics, jobs, technology leadership as well.
Despite all these advantages the challenges may not be forgotten:
- The relation costs versus benefits. The question will be which additional hybrid costs will
be accepted by the customer, which (cost) benefits can be achieved during a reasonable
time of operation
- To enlarge the ZEV range, to adapt the ICE to hybrid demands, to make hybrids
lightweight, safe and more robust, to increase the durability for heavy duty application
To reach the CO2 targets, the air quality goals and to secure sustainable mobility clear milestones and
recommendations are set in this document.
Milestones for Passenger Cars
Milestone 1: 2015. Adapted Hybrids. The already started and ongoing introduction of hybrids into
the market is based on the adaptation to existing vehicles.
ERTRAC Research and Innovation Roadmaps
Hybridisation of Road Transport page 4 of 45
Milestone 2: 2020. Integrated Hybrids. Vehicle & system integrated hybrids will provide efficiency
gains for all consumers. Mass production of Plug-In Hybrids and Range Extender Hybrids has started.
Milestone 3: 2025. Competitive Hybrids. Hybrid Vehicles competitive regarding costs and benefits
will conquer the market. Modular and flexible Hybrid Vehicle designs will make the market more
interesting.
Milestone 1: 2015. Optimised Truck. Distribution trucks with plug-in capability and long haul trucks
with tailored mild hybrid systems.
Milestone 2: 2020. Tailored Truck. Components tailored for high efficiency and durability w/wo
Range Extender, with Plug-In capability.
Milestone 3: 2025. Sustainable Truck. Hybrid systems with designed for hybridisation & continuous
grid connection.
Milestone 1: 2015. Tailored hybrid bus - with Plug-In capability
Milestone 2: 2020. Light weight hybrid and full electric Bus, w/wo Range Extender, with Plug-In
capability.
Milestone 3: 2025. Alternative energy converters systems designed for hybridisation
To reach the milestones a lot of research expenditure is necessary mainly for the following fields:
o Energy Storage Systems. Batteries smaller, cheaper, lightweight, safe, more robust,
long life time and with high power & energy density
o Drive Train technologies. New concepts for electrical machines & electro mechanical
technologies, low-cost, lightweight
o System Integration & Modular Hybrid Architecture. To build robust, small, integrated and
efficient hybrid configurations
o Grid Integration. Fast, contact-less, bidirectional charging infrastructure
Of course additional research efforts are to undertake in safety aspects and the integration of hybrids
into the transport system and the development of solutions capable for high number of pieces (mass
production).
The Hybrid Electric Vehicles are an essential part of sustainable mobility for a long time, they will
support the environmental goals, without Hybrid Electric Vehicles the CO2 and air quality targets
could not be reached. Full Electric Vehicles will dominate as pure city- and short distance solutions.
But, Hybrids will be the major solution for sustainable mobility, for individual mobility, for goods
transport and for public transport, suitable to enter cities as well, due to there ZEV range.
The European Commission should support the benefits of Hybrids, setting the standards to get the
lead, promote HEV research in the 8 th
Framework Programme.
2. Introduction
In its new Strategic Research Agenda, ERTRAC has addressed major societal challenges such as
decarbonisation in road transport, reliability of the road transport system and the need for safety
and security in road transports. Only to overcome these challenges will secure sustainable person
mobility (individual mobility with the choice of your own means of transportation as well as to use all
the possibilities of public transport) and goods transport for the future, a basic requirement that
humans will presuppose as self-evident also in the future.
The future will request a mix of vehicles and the offer of more CO2 low/energy efficient cars and
trucks to secure an individual and environmentally friendly mobility freedom and ‘green’ goods
transport.
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Figure 1: The context of Sustainable Mobility
In the context of sustainable mobility, with its individual mobility, public and goods transport, the
propulsion technology carry the main load to overcome the problems of environmental impact and
air quality. To secure mobility and goods supply in cities and conurbation will be a great problem to
solve in the future. It is expected that urban zones have to accommodate more and more people.
When looking at the evolution of propulsion technologies, hybridisation appears to be a large part of
the answer, even if vehicles with Internal Combustion Engines (ICE) will be the long to future solution
for Long Distance Freight Transport and probably for long distance travel with family cars.
With a similar approach as the ERTRAC–EPoSS–SmartGrids roadmap ‘Electrification of Road
Transport’, the aim of this roadmap on ‘Hybridisation of Road Transport’ is to give a consistent
overview, to show the different fields of application, to explain the challenges and benefits for
environment and customer, to point out the most promising configurations and to define the R&D
needs on a time-line, this for passenger cars and commercial vehicles.
ERTRAC Research and Innovation Roadmaps
Hybridisation of Road Transport page 6 of 45
Figure 2: The evolution of passenger road transport energy source and propulsion technology,
towards 2050
The electrification of vehicle drive trains is an important step to increase energy security,
improvement of air quality and CO2 reduction. Future customer demands combined with legal
requirements will drive the introduction of Hybrid Electric Vehicle (HEV) technologies, increasing the
energy efficiency of vehicles propelled by conventional power-trains which solely utilise fossil fuels,
while developing enabling technologies for the future large scale vehicle electrification. Without
brought hybridisation, especially with Plug-In Hybrids and Range Extender Hybrids, the goals of
decarbonisation could not be achieved.
Figure 3: The classification of Hybrids
As a first step to electrification start-stop and starter-generator systems are already in a market
penetration phase, pure Electric Vehicles (EV) are announced for the next years. A real series market
penetration is seen after 2020.
An essential question for the moment is however, if hybrid configurations, e.g. Plug-In Hybrid, Range
Extender Hybrid and other new hybrid solutions are the meaningful alternative to pure Electric
Vehicles at the end. The advantage of hybrid configurations lays in the stepwise transition to
electrification without giving away customer benefits.
We expect that hybrids will play a role for long time, more than today expected. Hybrids are one
solution to reduce CO2 and thus the answer for future CO2 legislation. This demand of the future
ERTRAC Research and Innovation Roadmaps
Hybridisation of Road Transport page 7 of 45
regarding sustainable mobility will show us as most build hybrid configurations the ‘Plug-In Hybrids’
as best utility for ‘allround’ cars and the ‘Range Extender Hybrid’ as a solution for conurbation.
It will be necessary to work besides pure city solutions on comfortable, affordable and
environmentally friendly solutions rechargeable for short to long distance use. This will be one of the
great hybrid challenges and with a proper answer a great step for future individual and sustainable
mobility.
New concepts with new engine and sub-system solutions, especially for hybrid configurations are to
be developed, one has to think about new hybrid means of transportation, solutions for pure short-
range city traffic as well as for long distance holiday trips.
The improvement, talking in this paper will be the supplement of ICE driven vehicles with all kind of
hybridisation features. We expect that most of the ICE driven vehicles are equipped with hybrid
features, from start-stop up to Plug-In devices.
o Links to other roadmaps and strategic papers
Vehicles with ICE will be the main platform for road transport for long time. A lot of research effort is
needed to improve the internal combustion engine. An important paper there comes from the
EUCAR Work Group Powertrain, ‘Research needs in light duty conventional powertrain
technologies’ published November 2010.
In the context of ‘Vehicles with ICE – Hybrid Vehicles – Electric Vehicles’ the ERTRAC–EPoSS–
SmartGrids roadmap ‘Electrification of Road Transport’ and the roadmap ‘Long Distance Truck’,
both developed in the frame of the European Green Car Initiative are to mention as a important
paper.
Obviously the European Commission has a great influence on the future vehicle development, papers
important for road transport are under others surely:
• The Transport White Paper setting the EU transport policy: COM(2011) 144, White Paper
2011 ‘Roadmap to a Single Transport Area – Towards a competitive and resource efficient
transport system’
• The strategy for clean vehicles : COM(2010) 186, A European strategy on clean and energy
efficient vehicles’.
There are also links to other European Roadmaps developed by ERTRAC Working Groups, as:
‘Integrating the Urban Mobility System’; ‘European Bus System of the Future’; ‘Sustainable Freight
System for Europe’; ‘Safe Road Transport’; ‘Future Transport Energies’; ‘European Technology &
Production Concepts for Electrified Vehicles’ and ‘Road User Behaviour & Expectations’
3. Benefits and challenges of Hybrid Propulsion
ERTRAC has recently issued scenarios and objectives for road based transport proposing that, with
the combined commitment and assumption of responsibility by all stakeholders concerned, transport
efficiency should become 50% more efficient by 2030 compared with today. This target is translated
into three main areas and a number of indicators with corresponding guiding objectives as shown in
table 1 below.
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Table 1: Summary of guiding objectives of ‘ERTRAC Strategic Research Agenda 2010; Towards a 50%
more efficient Road Transport System by 2010
The objectives for decarbonisation, set in the ERTRAC Strategic Research Agenda (SRA), are energy
efficiency gains of 80% for urban traffic and 40% for long distance freight transport.
Hybrid Vehicles will play a major role, they are absolutely necessary with regard to the societal need
for decarbonisation in road transport. They are a major enabler to reach the CO2 targets, to reduce
the Green House Gas emission in general. They will also play a role concerning the conventional fuel
resources dependence. Not to forget that they are helpful to enable good air quality in urban areas
due to the electric zero emission driving possibility. The aim of clean air in conurbation and the air
quality makes it necessary to find near zero emission solutions.
Since Hybrid Vehicles do not have the range limitations of full Electric Vehicles, they will be more in
line with the consumer’s needs and the driving pattern of today and those for the future.
ERTRAC Research and Innovation Roadmaps
Hybridisation of Road Transport page 9 of 45
Figure 4: The benefits of hybrid electric vehicles
Customer expectations on Hybrid Electric Vehicle properties are even higher compared to
conventional vehicles. No functional disadvantages may have the Hybrid Electric Vehicle (HEV), they
should offer new and additional benefits, like to drive as Zero Emission Vehicle (ZEV). An important
target is to reduce the fuel consumption in real life operation.
Hybrid Electric Vehicles combine the advantage of two different propulsion systems, the possibility
to drive with zero emission and to drive on long distances. They fulfil a lot of benefits as fast
highway driving, to pull supporters, they are thrifty and clean. Hybrids will be a good solution for a lot
of families to choose a car they can use in areas with worse air quality, probably in the future a lot of
them with restrictions for conventional cars, as well as to go on holidays.
Beside these benefits hybrids suits a lot of vehicle configurations – small city cars, long distance
family cars, delivery vans, city-buses. Plug-In Hybrids and Range Extender Hybrids will offer a range of
400 to 500 km with optional zero emission driving in electric mode and with ultra low emissions with
the optimised ICE mode in the future. An additional benefit for CO2 reduction can be obtained when
using bio-fuels from the 2 nd
/ 3 rd
generation. Alternative fuels, especially bio-fuels offer the possibility
to adapt the engine to dedicated fuel specifications. The reduced liquid fuel consumption of hybrids
offer the potential to bring demand and production capacity in line without penalties for food and/or
rain-forest.
The benefits shows very clear that the Hybrid Electric Vehicles will be an important part to secure
sustainable mobility
- Zero emissions in cities and conurbation, driving without making air quality worse
- Driving without limited range from city to city as well as all over the landscape, with
optimised ICE and transmission, the use of alternative-/bio-fuels and thus reduced fuel
consumption and lower emission.
With all these benefits, the use of hybrid vehicles will gain benefits on economics, jobs, technology
leadership as well.
But, the benefit of a hybrid configuration depends on a large number of influencing factors. An
optimum configuration can differ significantly depending on these factors. As nearly all factors
Vehicle with ICE:
Pure Electric Vehicle:
Hybrid Electric Vehicles:
- With ICE propulsion unlimited range and speed on the country side
- ZEV mode in conurbation
- As Range Extender and Plug-In with ZEV range up to some hundreds of kilometres
- Reduced CO2 emission
Hybridisation of Road Transport page 10 of 45
have some interrelations and due to the increased system complexity the system design is more
challenging than for conventional ICE vehicles.
Selected optimisation tasks and their interaction to the component properties are briefly:
1) In HEVs electric motors and power electronics have to be packed. In nearly every case the
available space and relation to this, the size of components is limited. Obviously, the size
correlates to the component properties, leading to a trade off in design and layout.
2) At the mounting locations these components are exposed to environmental conditions i.e.
temperatures and accelerations, which have to be taken into account for the design for a safe
operation.
3) The control of the components is done through specific control units, which have to be
connected to the vehicle communication network. The second torque source has to be
coordinated with the combustion engine torque.
4) An important aspect is the correlation of the system design and thus for instance the
frequency and the profile of the load of the individual components with the life time of the
components. It is known, that batteries can withstand only limited numbers of charge and
discharge cycles.
5) Also the power electronics, built out of materials with different extension coefficients have
limited life time cycles due to the active and passive temperature cycling.
6) For the majority of the customers, predictable system reaction is a prerequisite for
acceptance.
Source: ‘Challenges for electric energy storage systems in hybrid vehicles’; Braunschweiger Hybrid
Symposium, 21. Februar 2008
Operating at cold conditions, particularly reliable cold start behaviour is another sensitive
requirement of hybrid vehicles. Since state-of-the-art battery technology is not ready to meet this
completely, today a HEV suited to daily use will be equipped with an additional starter and even for
Plug-In Hybrid Vehicles (PHEV) an internal combustion engine will be strongly recommended for cold
conditions and as range extender.
The challenges to solve on the way to more sustainable electrified traffic, not only caused by the
system complexity, could be summarised as:
- First of all the reduction of the hybrid system costs, especially the costs of the batteries,
remains an important challenge. The energy and power density and thus the range of
batteries have to be increased. The weight and volume of hybrid storage systems is to
decrease, new architectures and materials for electric machines and storage systems are to
develop.
- The system operating strategy optimisation. The issues of range extender and boosting, the
new operation modes like start-stop function and two torque sources, adaptation of ICE to
hybrid requirements, downsizing, alterative fuels and charging requires thermal
management optimisation, battery and combustion optimisation. For an optimum system
design, in general robust, small, integrated and efficient hybrid components and
configurations are to build. For heavy duty application an increased durability is needed.
- New (fast) charging options at home, during working hours, in public areas, the needed
infrastructure is to provide (type and availability of loading stations and adequate power
grid, the way of data exchange between vehicle – power grid – energy provider) as well as
the necessary investment in production facilities and the flexible rebuilding of production
lines to react on market fluctuations.
- Hybrid solutions capable for high number of pieces are to develop.
ERTRAC Research and Innovation Roadmaps
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A further challenge or impediment in market growth could be restrictions in material availability, e.g.
for rare earth, magnetic materials.
Considering the large predicted growth in their market shares, a leading position of Europe in Hybrid
Vehicle Technologies is critical for the global competitiveness of the…